Foam finish applicator

ABSTRACT

A method for applying a solution to a moving textile tow includes the steps of preparing a fine bubble foam from the solution with air and applying the foam to opposite sides of the moving tow and then drying the coating. The apparatus includes a hollow applicator cylinder having a slot through its wall, a dispersion filter within the cylinder and sources of pressurized air and solution which are mixed and passed through one or more sintered material filters before reaching the applicator cylinder. A perforated plate is usually fitted in the slot.

States De Hewitt et a1.

1 atent 1 [451 Feb. 11, 1975 1 FOAM FINISH APPLICATOR [75] lnventors: .llack Renato De l-lowitt; Imre Mirko Jonkoif; Robert Ernest Stoveken, all of Camden, S.C.

[73] Assignee: E. 1. du Pont de Nemours and Company, Wilmington, Del.

[22] Filed: June 5, 1972 [2]] Appl. No.: 259,664

[52] 0.8. CI. 118/612, 118/411 [51] Int. C1. B05c 5/02 [58] Field of Search 118/410, 411, 612, 600; 239/243, 5903, 598; 68/200; 261/DlG. 26; 264/50 [56] References Cited UNITED STATES PATENTS V 2,533,167 12/1950 Kelham 68/200 X 2,678,024 5/1954 Kresse 68/200 X Am 1 SOLUTION lo 3,251,092 5/1966 Printz 264/50 X 3,418,970 12/1968 Phelps et a1. 118/410 3,466,690 9/1969 Cooper 15/50 R 3,751,755 8/1973 Smith 15/302 Primary Examiner-1ohn P. Mclntosh [57] ABSTRACT A method for applying a solution to a moving textile tow includes the steps of preparing a fine bubble foam from the solution with air and applying the foam to opposite sides of the moving tow and then drying the coating. The apparatus includes a hollow applicator cylinder having a slot through its wall, a dispersion filter within the cylinder and sources of pressurized air and solution which are mixed and passed through one or more sintered material filters before reaching the applicator cylinder. A perforated plate is usually fitted in the slot.

3 Claims, 4 Drawing Figures FROM FILTERED COMPRESSED AER SOURCE PATENIEBIFEBI 1197s SHEET 10F 2 ZOFDJOm EOE.

wUmDOm m qOwmmmmE2Ou|l owmmhJ E 20mm d m-L FOAM FINISH APPLICATOR BACKGROUND OF THE INVENTION This invention concerns apparatus for preparing and applying a coating such as a finish solution to a continuously moving textile web. More particularly, it relates to the application of a foamable solution to a textile tow of continuous filaments in a highly efficient and uniform manner with minimum waste.

In the past, it has generally been customary to apply finish to textile tow by passing tow over a finish application roll and then through squeeze rolls to remove excess solution. Many factors in this procedure affect uniformity, such as gradual drop in solution concentration, temperature, speed of tow, thickness of tow and squeeze roll pressure. Furthermore, the solution which is removed by the squeeze rolls is usually contaminated or diluted and therefore cannot be reused but must be disposed of. This puts an extra load on anti-pollution devices. In addition, solution applied in this way tends to migrate into the fiber mass if the tow is held in cans in preparation for combining with tow from other cans and drying. This results in loss of solution utility and sometimes necessitates reapplication of finish after the drying step.

Other means for applying solution to running tow include the plate and slot applicator as described by Latour in U.S. Pat. No. 3,199,492. Further improvement was realized by the apparatuses and methods disclosed by Sharp in U.S. Pat. No. 3,393,661, Baber in U.S. Pat. No. 3,422,796 and Carder in U.S. Pat. No. 3,511,730, all of which employ one or more applicator cylinders having a hollow central portion for receiving solution, applicator slot or channels from the inner portion to the outside of the cylinder and grooves cut in the outer surface of the cylinder to provide the fiber spreading. Although each of these techniques improved the uniformity and efficiency of solution application to tow, a need for further improvement resulted in the following invention.

SUMMARY OF THE INVENTION The preferred apparatus of this invention comprises a supply of solution, such as a textile finish, and a positive displacement metering pump for introducing solution at a predetermined uniform rate through a supply pipe and preliminary solution filterin means to one side of a pipe tee. A source of filtered high pressure air is connected through a throttle valve and a check valve to another side of the tee. The outflow from the tee is connected through one or more sintered metal filters and thence to an elongate cylindrical diffusion filter mounted coaxially inside a hollow applicator housing. This housing preferably is a cylinder that is provided with a longitudinal, coaxial, wide slot having fitted therein a perforated distribution plate or alternatively an adjustable narrow slot may be provided. This slot extends from the inner chamber of the cylinder containing the diffusion filter. Preferably, a pair of applicators is provided and arranged with suitable driven transport rolls and guide-rolls for threading the tow across a first and then across the second applicator cylinder so as to apply foam finish evenly to each surface of the tow in turn. The cylinders may be provided each with two collars the separation of which is adjustable to suit different tow widths. Likewise, a masking arrangement may be provided to cover part of the perforated plate applicator according to tow width.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a piping diagram and an elevational view in cross section to show certain details of a single foam producing and applying apparatus.

FIG. 2 is an enlarged plan view, from the outside, of a preferred perforated distribution plate.

FIG. 3 is a sectional view still further enlarged of a single hole in a perforated distribution plate; and

FIG. 4 is a side elevation of two applicators in position for applying foam to both sides of a moving endless tow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, the principal components of the apparatus are seen to be a foam producer, generally designated in the lower portion of the Figure as 10, arranged to mix air with a liquid solution to prepare a foam and an applicator assembly generally designated in the upper portion of the Figure as 100. A pair of these assemblies is employed in the preferred embodi ment in order to apply foam sequentially on both sides of a running endless web. The foam producer 10 includes a pipe 12 extending from a solution supply (not shown) to a positive displacement metering pump 14 (such as a Zenith pump) which pumps solution over pipe 16 into a conventional solution filter 18 (such as a Pall Trinity Filter Co., Model MDF-4463UP4). This filter is connected over pipe 20 to one side of a pipe tee 22. In a second leg of this foam preparation system, a pipe 24 extends from a filtered compressed air source (not shown) through a flow controller throttle valve 26 (such'as a Moore Products Co., Controller Model 63SD-3 1688) and connected needle valve. The output of valve 26 is connected over pipe 28 through a check valve 30 (such as Hoke Valve Co., No. 6133-F4S) and thence over pipe 32 to a second side of pipe tee 22. The output from tee 22 is connected over pipe 34 to a first prefoamer assembly 36 and thence over pipe 38 to a second prefoamer assembly 40. The output of prefoamer 40 is carried over pipe 42 to the foam applicator assembly 100. A pressure gage 44 of conventional design is connected over stub pipe 43 to pipe 42. Likewise, air actuated relief valve 46 is connected to pipe 42 over stub pipe 45 and is connected over output line 47 to a solution return line. In this embodiment, relief valve 46 is actuatable by a pneumatic diaphram arrangement 50 connected to an air line 48 extending from a web dryer interlock. Prefoamer filters 36, 40 are, in the preferrred embodiment, Hoke Valve Co. filters, Model 632-4-F4S with sintered metal cartridges therein. The filter medium is selected to have a nominal pore-size rating of 20 to 30 microns nominal with a flow coefficeint, Cy, of 0.39. In some cases, filters with pore sizes ranging from 5 to 55 microns have been employed but the range from 20 to 30 microns is preferred.

Pipe 42 is connected to foam applicator assembly by means of a modified Gyzrolok No. 8COS3I6 pipe fitting 102. The inner end of fitting 102 is threaded and arranged to screw into an appropriately threaded bore in one end of applicator cylinder 104. The inner end of the central bore of fitting 102 is reamed to permit a press fit of a final foamer and distributor filter cartridge 106. This final diffusion filter in the preferred embodiment is a Minnesota Mining and Manufacturing Co. closed end sintered metal filter cartridge or similar cartridge of bonded glass beads having pore size ranging from 17 to 20 microns. It has been found that pore sizes ranging from 10 to 30 microns may be used but the range of the preferred embodiment provide the best results.

Cylinder 104 has an axial slot 108 passing through the wall of cylinder 104 from the space 105 of the inner bore, just outside filter 106, out through the outer surface. This slot extends between two end portions 110, 110' of cylinder 104. A perforated distribution plate 112 is fitted into slot 108 and fastened to cylinder 104 at the end portions 110, 110'.

A support ring 114 is provided with a central bore arranged to receive one end portion of cylinder 104 and is attached to part of the overall machine support 116 by means one one or more bolts 118. Set screws, not shown, are provided to attach cylinder 104 to support ring 114 near one end of the cylinder. The inner edge 115 of ring 114 is made in the form ofa truncated cone. A second ring 120 is arranged with a bore to fit movably around the outer end of cylinder 104. This ring also has a partial conical surface 121.

A sealing block 122 is arranged in a slot 124 machined into ring 120 in alignment with the outer surface of distribution plate 112. Bolts 126 and spring washers 128 serve to hold block 122 against plate 112 at any desired position of ring 120 along cylinder 104.

A ring positioner screw 130 having a handle 132 is threaded through a threaded plate 134 attached to the outer end of ring 120. Positioner screw 130 has a smooth cylindrical end portion 136 of reduced diameter at its inner end. A pipe fitting 138 has a central bore dimensioned to receive end portion 136 therethrough. Part of portion 136 extends beyond the inner end of fitting 138 and has a slot carrying a retaining ring 140 therein. Thus, retaining ring 140 and shoulder 141 restrict axial motion between screw 130 and fitting 138, but allow relative rotation. A threaded portion of fitting 138 is provided on the inner end thereof and arranged to screw into an appropriately threaded bore in the outer end of cylinder 104. Since cylinder 104 is fixed to the machine frame by means of ring 114, screw 130 enables axial adjustment of the position of ring 120.

The perforated distribution plate 112 shown in FIG. 2 has outer dimensions arranged to fit into slot 108 and has a number of fine through holes in an arrangement selected to provide uniform distribution of foam forced therethrough. In the preferred embodiment, the holes are distributed in three lines extending over the length of plate 112 which is or may be uncovered between the inner edges of rings 114, 120. The separation between holes in the plate 112 along a given row of holes lengthwise over the plate was found to be optimum at about 3/32 of an inch (2.38 mm.) for the dimension d,. The holes in two adjacent rows are offset by a distance d which is typically l/32 of an inch (0.79 mm.). The separation between two rows of holes 5, was made 3/32 of an inch (2.38 mm.) in the preferred embodiment. However, this spacing is not critical since a wide range of separation is operable. As shown in FIG. 3, the individual holes have a modified funnel shape with a smaller inner diameter hole A, expanding to a larger diameter A, at the outer surface of plate 112. Converging holes have also been found operable. In the preferred embodiment, the dimensions employed for these diameters are 0.01 in. (0.25 mm.) for A, and H16 inch (1.6 mm.) for A,,. In practice, holes have been used with A, ranging from 0.005 inch (0.127 mm.) to 0.015 inch (0.381 mm.). Although this series of small spinnerettype holes placed in the perforated plate appears to perform most satisfactorily, a plate having one or more axial slots has also been found to operate satisfactorily in some situations.

FIG. 4 shows an end view of a typical stringup for applying finish to both sides of an endless moving tow wherein duplicate foam applicator assemblies 100, are arranged with perforated plates 112 and 112 oriented to receive one side of the tow against plate 112 and the opposite side of the tow against plate 112. In this way, uniform application of the finish on both sides is attainable.

In operation, the air and solution supplies are adjusted so that they mix and form a foam of acceptable density by passing through the first and second prefoamer filters 36, 40 and the final foamer and distributor 106. In the case of applying finish to the textile tow, it has been found that the range of use useful finish-toair ratios runs from 1:5 to 1:100. The optimum ratio used was within this range and gave bubble density and stability which was optimum for application to the tow. On measurement, it was found that foam density for acceptable operation may be maintained within a range of from 0.050 gram per milliliter to 0.175 gram per milliliter. In determining the above measurements, air pressure to the tee 22 was varied from 25 psig. to 50 psig. The finish composition used was a 20 percent aqueous emulsion of about:

50 parts Nonylphenylethylene oxide (9-11) (e.g., Igepol CO-7l0 a product of General Aniline & Film Corp.)

12 parts Oleic Acid 15 parts Triethanolamine 3 parts Diethylene glycol 14 parts Monoand di-alkyl ester of Phosphoric Acid 6 parts Boric Acid.

In the preferred embodiment, the normal point of operating would be with a foam density of approximately 0.085 gram per milliliter.

Successful performance of this invention has been demonstrated by applying textile finish to tow by the stringup of FIG. 4 where tow is supplied from cans and immediately deposited on a tow dryer bed after finish application. Sample-to-sample and edge-to-edge variability was found to be significantly improved over the convention method of finish application wherein the tow is saturated with finished solution by surface application and then put through squeeze rolls. In addition to improved uniformity in finish application, finish absorption was also lower. Foam application techniques provided in this invention also resulted in better bundle penetration with resultant improved processing characteristics for the tow in such processing machines as the Turbo Stapler where excellent continuity, low static and defect free sliver resulted. In addition, tow which had been processed by the technique of this invention was processed by a Pacific Converter without the addition of finish after the drying step. Finish was normally required for conventional liquid application.

A novel method of applying a solution to a moving web has been described along with a novel structure of apparatus for carrying out this method. Preferred ranges of conditions for carrying out the method and the preferred structure for application of the invention have also been specified. it is evident that one skilled in the art may find different structures for the apparatus which will operate satisfactorily and in addition may find varied operating conditions under which to practice the method of this invention.

What is claimed is:

1. An apparatus for preparing and applying a foam solution from a pressurized gas and a liquid finish to a textile web moving in a path including means for moving the tow in said path, said apparatus comprising: an elongated housing positioned across said path, said housing having walls forming an inner chamber and having a longitudinal slot through one wall, said slot being in communication with said chamber and disposed toward said path; a distribution plate fitted in said slot, said plate having outer and inner surfaces connected by a plurality of holes, said outer surface being adjacent said path, said holes expanding to a larger diameter at said outer surface; a source of liquid finish; a source of pressurized gas; means for mixing said liquid finish and said gas; and a diffusion filter positioned in said chamber, said filter being supplied with a mixture of liquid finish and gas by said means for mixing.

2. The apparatus as defined in claim 1, there being a pair of said housings, one on each side of said path to apply foam solution to opposite sides of said web.

3. The apparatus as defined in claim 1, including means for adjusting the length of said slot to accommodate different web widths.

i= =l i 

1. An apparatus for preparing and applying a foam solution from a pressurized gas and a liquid finish to a textile web moving in a path including means for moving the tow in said path, said apparatus comprising: an elongated housing positioned across said path, said housing having Walls forming an inner chamber and having a longitudinal slot through one wall, said slot being in communication with said chamber and disposed toward said path; a distribution plate fitted in said slot, said plate having outer and inner surfaces connected by a plurality of holes, said outer surface being adjacent said path, said holes expanding to a larger diameter at said outer surface; a source of liquid finish; a source of pressurized gas; means for mixing said liquid finish and said gas; and a diffusion filter positioned in said chamber, said filter being supplied with a mixture of liquid finish and gas by said means for mixing.
 2. The apparatus as defined in claim 1, there being a pair of said housings, one on each side of said path to apply foam solution to opposite sides of said web.
 3. The apparatus as defined in claim 1, including means for adjusting the length of said slot to accommodate different web widths. 